The policies, issued in response to a civil rights lawsuit by the ACLU, clarify how prosecutors must abide by a half-century-old U.S. Supreme Court decision regarding exculpatory evidence. Lacey said it was vital her prosecutors comply with the rule of law.

Jackie Lacey, the newly-elected Los Angeles County District Attorney speaks at news conference in Los Angeles. Lacey made history by becoming the first African-American and first female chief prosecutor of Los Angeles County. Responding to a civil rights lawsuit, the Los Angeles district attorney issued a special directive to prosecutors on June 11, 2013 ordering them to "play fair" and hand over to defendants evidence favorable to their cases including background on peace officers and other government employees. (AP Photo)

"The integrity of the criminal justice system requires that prosecutors play fair in seeking justice," Lacey, who took office in December, said in a statement. "When in doubt, we want our prosecutors to disclose the evidence and litigate its admissibility in a court of law."

The suit also challenged a policy adopted by former District Attorney Steve Cooley that allegedly prevented — and in some cases explicitly prohibited -- prosecutors from disclosing evidence of police officer misconduct. In many cases, it claimed, abused inmates were regularly charged for the alleged assault of any deputy involved.

It said the system of Brady violations, named for the Supreme Court case, may have barred numerous defendants from receiving a fair trial.

The ACLU dropped its lawsuit early this year after Lacey agreed to address how her office disclosed evidence of misconduct by police officers and other government workers. The advocacy group praised the DA for directing such evidence be disclosed to criminal defendants as required by state and federal law.

"We commend her for demonstrating such strong leadership and taking seriously the district attorney's constitutional obligations to ensure fair trials," said Hector O. Villagra, executive director of the American Civil Liberties Union of Southern California, in a statement.

Lacey's office claimed her two policies only summarized the existing legal obligations of local prosecutors. The ACLU maintains it represents a change in how evidence must be disclosed.

For example, evidence of officer misconduct not included in a so-called Brady Alert System, or database for offending officers, must now be presented to defense attorneys. The policies also require prosecutors fully disclose all evidence favorable to defendants, per state law, and not withhold potential evidence just because they think it's false.

Two weeks after the ACLU lawsuit, Baca quietly revamped his policy on how complaints of use of force were filed against jail deputies. Rather than be placed in inmate files, where they were likely not to be discovered by defense attorneys, complaints are now lodged in officer files. The ACLU later dropped its claims against the Sheriff's Department.